A cross-point memory device having a three-dimensional structure has been developed. The cross-point memory device may easily achieve high integration, and provide a high-speed operation by using a resistance change material for the memory cell thereof. For example, such a memory cell has a structure combining a memory element and a rectifying element. The memory element contains a resistance change material, and is connected in series to the rectifier element.
The rectifying element acts to avoid data reading from an unselected memory cell and data writing thereto among plural memory cells that are connected in parallel. Thus, the rectifying element may preferably have a high ratio of a forward current to a backward current (ON/OFF ratio). For example, a p-n junction diode using silicon as a material has a high ON/OFF ratio.
Although the silicon diode is easily manufactured, the manufacturing process of the silicon diode may include a step with a thermal treatment of 800° C. or higher, deteriorating the characteristics of the resistance change material in some cases. In addition, there is a limit to reducing the size of the silicon diode, thus becoming an obstacle to miniaturize the memory cell. Hence, a rectifying element is required that has a high ON/OFF ratio and is easily miniaturized without deterioration of the resistance change material, and a memory cell structure suitable therefor is also required.